An Article to Help You Understand the Similarities and Differences Between KYN61-40.5, KYN28A-12, and KYN28A-24

First, their basic configuration is the same: the "K" stands for metal-clad, meaning they all use metal plates such as high-quality aluminum-zinc coated steel plates bolted together to form a sturdy, fully enclosed metal shell. The "Y" indicates that all three adopt a withdrawable design, where the vacuum circuit breaker is installed on a movable trolley. The "N" stands for indoor installation, meaning they must be installed in dedicated power distribution rooms and cannot be directly exposed to outdoor environments.

Secondly, they all feature strict compartment segregation, divided into four isolated metal compartments: the busbar compartment, the circuit breaker trolley compartment, the cable compartment, and the relay and instrument compartment. The busbar compartment is located in the upper rear part of the cabinet, housing the main and branch busbars. The cable compartment is situated in the lower rear part, used for connecting incoming and outgoing cables, and for installing components such as current transformers, voltage transformers, and grounding switches. The relay and instrument compartment is located in the upper front part, where secondary control components like microprocessor-based protection devices, meters, indicator lights, and buttons are installed. The circuit breaker trolley compartment is in the middle part of the cabinet, serving as the space where the trolley is inserted and operates.

In addition, they are all equipped with five protection interlocking functions, achieved through mechanical or electrical interlocks to:

1.Prevent the trolley from being inserted or withdrawn under load.

2.Prevent power from being supplied with the grounding wire connected.

3.Prevent the grounding wire from being connected while the circuit is energized.

4.Prevent incorrect opening or closing of the circuit breaker.

5.Prevent access to live compartments (the cabinet door cannot be opened when high voltage is present).

They all have the functions of receiving and distributing electrical energy, as well as controlling, protecting, and monitoring circuits. They are used in substations, industrial plants, and large building power distribution systems, operating at different stages of the power distribution chain according to their voltage levels. Their main switching component is the vacuum circuit breaker, and the insulation medium is air.

The above are their similarities. The differences lie in their voltage levels and application scenarios, which show significant distinctions. KYN28A-12 is the most widely used and classic Switchgear cabinet model in China's medium-voltage power distribution field, serving as the standard switching equipment for most 10kV power distribution systems. KYN28A-24 has a higher voltage level than KYN28A-12. Due to the higher voltage, the electrical clearance (distance between live parts in the air) and creepage distance (distance along the insulation surface) inside the cabinet must be much larger than those of the 12kV cabinet. Its dimensions are also larger, its components are larger in specification, and its required electrical performance is stronger. KYN61-40.5 differs significantly from the KYN28 series in design philosophy and structure. Due to the high insulation distance requirements for 35kV voltage, its size is very large. Although it also uses a withdrawable design, its trolley is very heavy and usually requires a dedicated transfer cart for insertion and withdrawal operations. The air clearance requirements inside the cabinet are strict.

Such designs give them unique functions and advantages. They enable maintenance without power interruption and rapid fault recovery. When a circuit breaker needs maintenance or fails, the faulty trolley can be withdrawn and a spare trolley inserted, completing the entire process within tens of minutes and minimizing power interruption for important loads. Safety performance is also significantly improved through the physical standardization of the "three trolley positions (service, test, maintenance)" and the "five protection interlocking." Regardless of who the operator is or which substation they are in, they must follow this mandatory safety procedure, greatly eliminating the risk of human error. They provide extremely high configuration flexibility and scalability. Based on the standardized cabinet and trolley design, users can easily configure different functional circuits (such as incoming and outgoing lines, metering, interconnection, capacitor compensation, etc.) in the same row of switchgear cabinets. During later expansion or modification, it is only necessary to add or replace the corresponding trolleys and cabinets, offering excellent scalability.

If you need more knowledge about the KYN product series, please feel free to consult us. Our company, Hangbian Electric Technology Co., Ltd., has deep expertise in the medium-voltage power distribution field. We have the following core advantages for this product series and have successfully provided reliable solutions for many customers.